While some major sites remain unharmed —Herodium, for instance, is protected by a nearby Israeli military base—in many places the scale of the destruction is almost industrial. Looters attack ancient sites with backhoes and small bulldozers, scraping away the top layer of earth across areas the size of several football fields. Then, guided by metal detectors—coins often give away the location of other goods—they sink shafts to extract anything of value. Among the rock-hewn tombs that honeycomb the hills around Jenin, Nablus, Bethlehem, and Hebron, grave robbers methodically clean out each centuries-old chamber, dumping the bones and hauling off the limestone ossuaries.

In Sair, a town perched on a hillside northeast of Hebron, a middle-aged man speaks with pride of looting as his "work"—the only job he's ever known: "After the occupation [in 1967], when we were boys, there wasn't anything to do or anything to eat. So all of the people went to dig in the archaeological sites. And I saw what they could find." Four decades later, circumstances remain much the same. "Our economy is damaged," says another man who sells illicit antiquities. "We need to feed our families."

Palestinian law forbids looting of archaeological sites, as well as trade in, or possession of, antiquities. But the pillage proceeds unchecked. Sentences are light, typically a few weeks in jail. Critics say the Palestinian Authority could do more to educate its people about the value of their archaeological heritage. Yet both Palestinian and Israeli authorities are hindered by the West Bank's jigsaw of jurisdictional lines.

Under the 1993 Oslo Accords and subsequent agreements, Palestinian officers are supposed to have jurisdiction in cities, towns, and some large villages. They can also enter areas jointly controlled by the Palestinian Authority and Israel, but only after notifying the Israeli military. Entering territory governed solely by Israel (which encompasses some 60 percent of the West Bank) is, practically speaking, forbidden. Palestinian officers who risk going in usually keep a low profile, wearing plain clothes and carrying no weapons. Given such limitations, the outcomes are predictable.

A typical story: One night Namr Boja and five other Palestinian officers went unarmed to arrest villagers near Bethlehem who were digging through tombs. "We shouted, 'We are police! Stop!' " he recalls. "But they surrounded our group and attacked us with rocks."

Israeli soldiers, for their part, can rangeeverywhere. Yet because Palestinians consider any show of Israeli force in the West Bank a provocation, Israel's civil administration is reluctant to send soldiers to drive off looters. "We can't protect sites next to Palestinian villages," says an exasperated Yitzhak Magen, archaeological staff officer for Judaea and Samaria, Israel's term for the West Bank. "We can't go there."